1. Field of the Invention
The present invention relates to an AC-to-DC power converter, especially to an AC-to-DC power converter with low standby power consumption when in light load or empty load, used to comply with the green or power saving demand.
2. Description of the Related Art
To reduce the power consumption of an AC-to-DC power converter when in light load or empty load, a conventionally adopted solution is to place an additional switch device, such as a relay or a MOSFET transistor, at the entrance of an AC power to provide a mechanism for disconnecting the AC power and therefore comply with a standby demand. However, there are some drawbacks in placing the additional switch device at the entrance of an AC power. First, it may increase the production cost. Second, it may decrease the efficiency of the power conversion. Third, it may cause challenge to the heat dissipation. These drawbacks may deteriorate the performance of the AC-to-DC power converter, and cause vendors of the AC-to-DC power converter to suffer a higher operation expense. Therefore, there is a need to implement a cost effective AC-to-DC power converter with low standby power consumption when in light load or empty load, without deteriorating the efficiency of power conversion or heat dissipation.
To overcome the drawbacks of the conventionally adopted solution for implementing an AC-to-DC power converter with a standby demand, the present invention proposes a novel solution for the standby demand of an AC-to-DC power converter, needless of placing an additional switch device at the entrance of an AC power to disconnect the AC power.
The power converter of the present invention is designed to have a normal conversion mode and a freeze mode. The power converter of the present invention can be enabled to operate in the normal conversion mode, or disabled to operate in the freeze mode to comply with the standby demand of consuming extremely low power, when the loading condition is light load or empty load.